Stainless steel pipe is manufactured using a continuous plate and UOE process for thin wall pipe with a diameter of 219mm(8.6") and below, continuous compaction is used for pipe above 219mml8.6" and above, the UOE process is used. Continuous compaction equipment uses single or multi-torch P+T welding, while UOE is used on thick wall pipes of approximately 6m or 12m length using plasma welding. P+T welding. Plasma TIG and SAW. Remartinis required for internal shaping of pipe.
The plasma welding process is used on pipes with a wall thickness of 4mm(0.15") and above, the plasma keyhole creates a good penetration which can shape and weld each side of the pipe. For example, a 3-8mm(0.1"-0.3") wall thickness that is not bevelled requires only one pass. Tubes with a wall thickness of 8mm(0.3") and above require a bevel and a land for a plasma root pass weld.